Retrospective baseline measurement of self-reported health status and health-related quality of life versus population norms in the evaluation of post-injury losses
- 1Monash University Accident Research Centre, Melbourne, Victoria, Australia
- 2Centre for Health Economics, Monash University, Melbourne, Victoria, Australia
- Correspondence to: Dr W Watson Monash University Accident Research Centre, Building 70, Monash University, Melbourne, Victoria 3800, Australia;
- Accepted 11 September 2006
Background: Owing to the difficulty in prospectively measuring pre-injury health status and health-related quality of life (HRQL) in an injured cohort, population norms or retrospective baseline scores are often used as comparators for evaluating post-injury losses. However, there has been little discussion in the literature or research into the soundness of these approaches for this purpose.
Objectives: To investigate the appropriateness of the retrospectively measured baseline health status and HRQL in an injured population for the purpose of evaluating post-injury losses.
Methods: A cohort of injured admitted to hospital (n = 186) was followed up for 12 months after injury. Retrospectively measured pre-injury health status and HRQL scores were compared with those at 12 months after injury for participants who reported complete recovery (n = 61) and those who did not. Retrospective baseline scores for the whole cohort were also compared with Australian population norms.
Results: For participants who completely recovered, no significant difference was observed between scores at baseline (measured retrospectively) and those at 12 months after injury (36-item Short Form Questionnaire physical component summary z = −1.274, p = 0.203; 36-item Short Form Questionnaire mental component summary z = −1.634, p = 0.102; Short Form 6 Dimensions: z = −1.405, p = 0.296). A borderline significant difference was observed in HRQL as measured by the Assessment of Quality of Life (z = −1.970, p = 0.049). Retrospectively measured pre-injury scores were consistently higher than Australian norms for all measures.
Conclusions: The injured population may not be representative of the general population. Consequently, retrospective baseline measurement of pre-injury health states may be more appropriate than general population norms for the purpose of evaluating post-injury losses in this population.